Abstract: The present invention relates to a combustion control device incorporated in an apparatus such as water heater and provides the combustion control device having an improved configuration with a main controller and a sub controller, capable of employing a microcomputer with lower capability as the sub controller, and ensuring higher safety than ever before. Signals indicating a combustion state of a combustion apparatus are inputted into the main controller 35 and the sub controller 36 in parallel. Upon fulfillment of a predetermined condition of stopping, the main and sub controllers 35 and 36 each output a stop signal to cut off a current to be supplied to a device driving circuit 42. The conditions of stopping in outputting of the stop signal by the main and sub controllers are such that the sub controller 36 is less apt to execute the cutoff than the main controller 35.

Abstract: A floor working machine including a self-propelled vehicle body including a working implement for treating a floor surface; U-turn control means for causing the self-propelled vehicle body to make a U-turn automatically to adjust the working implement to a work line adjacent a work line treated before said U-turn; spin turn control means for causing the self-propelled vehicle body to make a spin turn automatically to align said working implement to a work line treated before the spin turn; and running control means for automatically controlling said U-turn control means and the spin turn control means in response to input signals for causing the self-propelled vehicle body to make selectively a U-turn under control of the U-turn control means and a spin turn under control of the spin turn control means.